In recent years, various post processing apparatuses have been developed, which conduct various post processing processes, such as a hole-punching process, a sheet-folding process, and a sheet-binding process, onto sheets which carries images formed by an image forming apparatus, such as an electro-photographic copying device, a printing device, a facsimile device, or a compound-machine having the functions of the above devices. Further, image forming systems, in which the post processing apparatus and the image forming apparatus are electrically combined, are generally used as the image forming systems.
In order to exactly conduct delivery and receipt operations of the recording sheet, ejected from the image forming apparatus, it is necessary for the post processing apparatus and the image forming apparatus to be accurately positioned in relationship with each other. For determining the positional relationships between them, they are combined by screws at their combining sections (see Unexamined Japanese Patent Application Publication No. 2002-128369). According to said Patent Document, the combining section of the post processing apparatus is assembled to be a movable part in the vertical direction, whereby after the combining section of the post processing apparatus is adjusted to the combining section of the image forming apparatus, both of the combining sections are secured to each other by the screws.
On the other hand, in recent years, speeded up operation and fined image formation are required to the image forming apparatus, and more speeded up operation is also required to the post processing apparatus. However, during binding operation, hole-punching operation, and folding operation, mechanical vibration and impact are adversely generated, wherein the impact is specifically and greatly generated during the binding operation. Further, due to the speeding up of the image forming apparatus, the number of the recording sheets to be processed becomes greater, the more impact is generated.
If the image forming apparatus and the post processing apparatus, disclosed in Unexamined Japanese Patent Application Publication No. 2002-128369, are combined, most of the vibration and the impact, generated in the post processing operation of the post processing apparatus, reach the image forming apparatus, which result in the reduction of an image reading accuracy.
To overcome this problem, a technology is disclosed in that a vibration control member is sandwiched between an image reading section of the image forming apparatus and an image forming section, integrally combined with the post processing apparatus (see Unexamined Japanese Patent Application Publication No. 2008-141304).
However, according to the technology of the latter Patent Application, the vibration and the impact, generated by the post processing apparatus, directly reach the image forming section, and since the image reading section has been mounted on the image forming section, when a bundle of a large number of recording sheets are to be finished, the image reading section adversely receives no small effect, though the vibration control member has been used. Further, if the vibration control member is mounted in the vertical direction, the weight of image reading section and a document feeding device, both mounted on the vibration control member, compresses the vibration control section, which results in the reduced effect of the vibration control member. Still further, based on the difference of the weight of units to be mounted on the vibration control member, the effect of the vibration control member changes, so that the units to be mounted are limited, which is a major problem.